Dr. Jon Hallberg: Your heart does more than love

On this day when the heart is featured in a starring role, MPR medical analyst Dr. Jon Hallberg and MPR's Tom Crann discussed how the vital organ works and whether there's any truth to the idea that a person can die of a broken heart.

Hallberg is a physician in family medicine at the University of Minnesota and director of the Mill City Clinic.

An edited transcript of that discussion is below.

Tom Crann: In this culture, the heart is the symbol of love and the seed of passion and emotion, too. Is there any medical basis for that?

Dr. Jon Hallberg: Well, I think for thousands of years, humans have made this association that when you are full of rage, your heart is beating in your chest. When you are calm, it is something you're not even aware of.

We know now, of course, that there is this very interesting interplay between the brain and hormones and stress and all kinds of things that make the heart feel the way it does, but there's no question that ... when you feel something emotionally, you feel it in your chest, and I think that's been the case and is the case.

Tom Crann: All right, give us the definition of the heart. It's a muscle, we're always told, right?

Hallberg: Yes, it's a fist-sized muscle that has four chambers and four valves. Its very simple purpose is to take blood that has given away its oxygen, bring it back to the lungs, put oxygen back in the blood, and then pump it throughout the body. And this just continues over and over again in a very carefully choreographed way that happens over and over and over.

Crann: But the heart is also almost literally wired to the rest of our body, right?

Hallberg: Yes, I think we forget about that. It's a muscle, but it has this very intricate, beautiful electrical wiring pattern that when it works well, it's sort of a thing a beauty and really kind of boggles the mind how well it works.

Crann: There are all sorts of ways to measure the heart in the clinic, exam it, including the old stethoscope. What are you listening for when you listen to someone's heartbeat?

Hallberg: Well, when we place our stethoscope on a person's chest, we're listening in four specific areas that correspond to the four valves in the heart. And the valve is designed so that blood only goes one way, that it doesn't sort of flow back in, and that's assuming that the valves are working well.

And when we listen, we can hear the sort of crisp click or a snap in a way that you can tell that the valve is closely tightly. What we're listening for is when it's not working well, if we hear a certain whooshing sound that would indicate that it's not working quite right, it's either too tight or it's too leaky.

Crann: And then when you get an EKG done, what does that tell you? Is that checking the wires and how the electricity's running through the wires?

Hallberg: Yes, it's taking advantage of the fact that there is this sort of electrical thing going on inside the heart. And when patient lays down and then they get those little leads stuck on them, we are getting basically 12 small snapshots that if we put it together in our minds, we can kind of create a three-dimensional picture of the heart.

Hallberg: Well, technically, no. When we've had a skipped heartbeat, what's really happening is that the heartbeat that should've occurred when it did actually came a little early. So you get two beats, kind of the one that was occurring and then right after that, you get another one. And then there's a pause, and it's that pause where we get that sense that something has skipped.

People will describe sort of a hollow feeling in their chest, this kind of emptiness, and then it's kind of followed by a thump, because that's then the beat that's coming when it should, and it feels like a little bit of a kick or a bump in the chest sometimes.

Crann: And then there's this concept we talked about of a broken heart, but can it cause physical damage?

Hallberg: You can get a broken heart. When people are hit with a great deal of stress, for reasons we don't fully understand, but clearly related to stress hormones, a surge of stress hormones, the heart muscle can get very thick, and the overall heart can enlarge. It's something we call cardiomegaly, a big heart.

It can feel like a heart attack, but when we do the measurements, there's no evidence that there's a heart attack. It's just big, and thankfully, it goes back down to normal size after about a week or so.

Crann: So on Valentine's Day, how resilient is the human heart?

Hallberg: The heart is amazingly, mind-bogglingly resilient. And I think maybe the simplest way to think about this is this fact, that if we say that a heart beats once a second, so 60 beats in a minute, that's 3,600 beats in an hour. That's about 86,000 heartbeats in a single day, over 31 million beats in a year. And... if we're lucky enough to live to be eighty years old, our heart has beat 2.5 billion times in that lifetime.